Hybrid vehicles may include an internal combustion engine and an electric motor to provide propulsion force to vehicle wheels. The hybrid vehicle may provide the performance and functionality of a vehicle having a larger displacement internal combustion engine via a smaller displacement internal combustion engine and the electric motor. The electric motor may augment engine torque during high driver demand conditions so that the vehicle may be provided torque that is similar to that of a larger displacement internal combustion engine. However, the electric motor may not be able to assist the smaller displacement engine during conditions when battery state of charge (SOC) is at a lower level. One way to reduce the possibility of having an insufficient amount of torque available at the electric motor is to increase battery pack size so that a battery supplying power to the electric motor stores a greater amount of electrical energy. However, adding additional battery pack increases battery pack cost and battery pack volume. Therefore, it would be desirable to provide additional charge storage capacity and additional charge souring capacity without having to increase battery volume.
The inventors herein have developed a system for operating a battery pack of a vehicle, comprising: a battery pack including a plurality of battery cells; and a controller including non-transitory instructions for adjusting battery pack state of charge operating thresholds in response to vehicle mass.
By adjusting battery pack state of charge operating thresholds in response to vehicle mass, it may be possible to provide the technical result of increasing stored charge in a battery so that a vehicle may be propelled for a longer period of time via an electric motor when vehicle mass increases. Additionally, the battery discharge amount may be increased so that the battery may be discharged to a lower level when vehicle mass increases. In this way, an electrical motor propelling a vehicle may operate for a longer period of time as compared to if battery state of charge operating thresholds were not adjusted. Further, the battery pack charging and discharging power may be adjusted in response to vehicle mass so that additional motor torque may be provided when vehicle mass increases.
The present description may provide several advantages. In particular, the approach provides for a way to increase an amount of energy and/or power delivered by a motor to a vehicle driveline. Further, high duty vehicles may be operated at higher loads where a battery SOC window is extended; however, the SOC window extent may be decreased when the high duty vehicle is operated at lower loads so that battery life may be extended. Further still, the approach also improves the rate of battery charging and discharging as vehicle mass increases.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.